textproduct: Rapid City

KEY MESSAGES

- Elevated fire weather conditions this afternoon.

- Pattern change today as cold front settles in later tonight. Cooler with precipitation chances through the week.

DISCUSSION

(This Evening Through Saturday) Issued at 1236 PM MDT Sat Oct 10 2026

Upper level analysis shows broad southwesterly flow across the Northern Rockies into the Northern Plains. Deep troughing is noted across the western US with closed upper low dropping into WA with a second closed low off the southern CA coast. Surface low pressure is centered over central ND with a cold front extending westward through southeastern MT, slowly pushing into far northwestern SD. Surface winds in northwestern SD have shifted out of the northwest, with west-southwesterly winds across the rest of the CWA. Very hot today with widespread 80s and to low 90s, warmest across the western SD plains.

Isolated showers and a few lightning strikes are possible later this afternoon and evening hours as shortwave trough pushes into the region. Given dry boundary layer, lack of appreciable moisture, and isolated coverage, precipitation amounts will be light and spotty. However, gusty winds are possible with any precipitation cores. The cold front will settle southward into the forecast area tonight. Cooler temperatures behind the front, although frontal position a bit uncertain Sunday. Current thinking is that the front will be slow to push south of the area, allowing for warmer temperatures along SD/NE border (70s) and cooler temperatures northward through Sunday afternoon.

Cold front will shift south of the area by Monday with cooler, yet near seasonable temperatures through the rest of the week. Active southwesterly flow aloft coupled with moisture influx from the remnants of Tropical Storm Rachel will support precipitation chances late Sunday into Monday, although best precipitation chances will be displaced north and northwest of the forecast area. A deep upper low is forecast to push through the area late Tuesday into Wednesday with another chance of precipitation Wednesday.

Forecast confidence wanes beyond Wednesday with considerable spread among the models/ensembles regarding the synoptic evolution.

AVIATION

(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 455 PM MDT Sat Oct 10 2026

Light showers/isolated thunderstorms will continue to affect NE WY to far western SD early this evening before dissipating. An approaching system will bring a cold front and NW winds to the area overnight. Better chances of showers are expected late tonight and Sunday morning across portions of NE WY and NW SD, where MVFR/possible IFR CIGS may also develop. These low CIGS may drop southward to near the I-90 corridor through afternoon.

FIRE WEATHER

Issued At 1236 PM MDT Sat Oct 10 2026

Very warm and dry today with near-critical fire weather conditions across portions of southwestern SD and the western SD plains. Temperatures in the 80s and 90s coupled with relative humidity bottoming out in the teens will result in near-critical conditions, especially ahead of the cold front currently in SE MT/NW SD. Winds generally remain below RFW criteria today, however transient gusts in excess of 25 mph are possible through the afternoon. Winds will shift out of the northwest across southwestern SD and western SD near daybreak Sunday, although relative humidity will be notably higher tomorrow (minimum RH 35-45 percent across SW SD and near NE/SD border; even higher north of I-90).

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.